The Dow Jones Industrial Index, or the Dow Jones Industrial Average, provides the average value of 30 big-name stocks. A high value indicates a healthy economy, while a low value often signifies that the economy is not doing well.
To calculate the average value, the prices of the stocks in the index are added and then divided by a divisor, which is changed as needed as stocks split. If a company's stock is falling while other stocks in the Dow index are rising, that can be indicative of an issue with the company. The list of companies that makes up the index is not fixed.